Modeling and Characterization of Phonon Transmission and Generation across Engineered and Strained Interfaces for Developing Structure-Property Relations of Functional Nanostructures.

摘要

The Air Force is increasingly relying on the benefits of novel multifunctional materials. These materials are being pushed to their thermal limits in progressively more demanding roles. Therefore, there is a strong need to develop modeling and characterization tools for better understanding of thermal transport in nanostructured functional materials. The objective of this project is to develop an integrated modeling and characterization tool to study phonon transmission and generation across engineered and strained interfaces. Such a tool will be critical in understanding the fundamentals of energy transport and in developing structure-property relations of functional nanostructures that could enable novel design of multi-functional nanostructures with superior thermal properties, such as super-thermal insulators, high efficiency thermoelectric materials, and super-thermal conductors. The accomplishment of this project include: 1). developed an atomic Green's function based-method for phonon transmission calculations, 2). developed a novel approach to measure phonon mean free path, and 3). studied the thermal transport in a few emerging materials such as hybrid organic-inorganic materials and two-dimensional materials such as transition metal dichalcogenides.